Bottom Line:
We found that both IL-1 and its receptor were expressed in uterine tissues before and after ovulation (in the pre-ovulatory stage, even before the yolk had formed in the ovary).However, while IL-1alpha was mostly localized in the uterine mesenchyme tissue, IL-1beta and IL-1RtI were present in the uterine epithelium.Our data provide a further comparison between the reproduction of mammals and squamate reptiles.

ABSTRACTWe recently showed that interleukin-1 (IL-1) is secreted by the placenta of a species of squamate reptile, the three-toed skink, Chalcides chalcides. In this study, we used immunohistochemical techniques to investigate the expression of IL-1 (in the two isoforms, IL-1alpha and IL-1beta) and its specific membrane receptor IL-1 RtI in uterine oviduct during the peri-implantation period. We found that both IL-1 and its receptor were expressed in uterine tissues before and after ovulation (in the pre-ovulatory stage, even before the yolk had formed in the ovary). However, while IL-1alpha was mostly localized in the uterine mesenchyme tissue, IL-1beta and IL-1RtI were present in the uterine epithelium. Our data provide a further comparison between the reproduction of mammals and squamate reptiles.

Figure 1: Uterus of Chalcides chalcides at the pre-ovulatory vitellogenic stage. A (negative control: without primary antibody). The uterine mucosa is thrown up into many long folds. Basal to the luminal epithelium (E) of low columnar cells, a lamina propria with numerous blood vessels (V) and the myometrium with outer longitudinal (L) and inner circular (C) layers are evident. B A strong immunoreactivity for IL-1α in the connective tissue and glandular cells of the lamina propria (arrows), and a weak reaction in the myometrium (*), where only a few epithelial cells are positive (arrowheads). C. Widespread immunoreactivity for IL-1β is seen in the luminal epithelium and in the myometrium. D. Immunoreactivity for IL-1R tI in the luminal epithelium (arrows), myometrium and cytoplasm of glandular cells (*). Bars = 25 μm.

Mentions:
The uterine wall of Chalcides chalcides consists of several distinct layers: an outer thin serous membrane, a middle myometrium formed by an outer longitudinal and an inner circular smooth muscle layer, and an inner endometrial layer formed by luminal epithelium with cuboidal or low columnar cells and a lamina propria of connective tissue with blood vessels and alveolar glands. During the pre-vitellogenic and vitellogenic phases (Fig. 1), the endometrial layer is organized in folds separated by deep furrows. Immediately after ovulation (Fig. 2), the uterus distends around each developing egg to form an incubatory chamber. The folds decrease in length and in correspondence to the equatorial region of the egg, the folds become larger, adhering to the shell membrane.

Figure 1: Uterus of Chalcides chalcides at the pre-ovulatory vitellogenic stage. A (negative control: without primary antibody). The uterine mucosa is thrown up into many long folds. Basal to the luminal epithelium (E) of low columnar cells, a lamina propria with numerous blood vessels (V) and the myometrium with outer longitudinal (L) and inner circular (C) layers are evident. B A strong immunoreactivity for IL-1α in the connective tissue and glandular cells of the lamina propria (arrows), and a weak reaction in the myometrium (*), where only a few epithelial cells are positive (arrowheads). C. Widespread immunoreactivity for IL-1β is seen in the luminal epithelium and in the myometrium. D. Immunoreactivity for IL-1R tI in the luminal epithelium (arrows), myometrium and cytoplasm of glandular cells (*). Bars = 25 μm.

Mentions:
The uterine wall of Chalcides chalcides consists of several distinct layers: an outer thin serous membrane, a middle myometrium formed by an outer longitudinal and an inner circular smooth muscle layer, and an inner endometrial layer formed by luminal epithelium with cuboidal or low columnar cells and a lamina propria of connective tissue with blood vessels and alveolar glands. During the pre-vitellogenic and vitellogenic phases (Fig. 1), the endometrial layer is organized in folds separated by deep furrows. Immediately after ovulation (Fig. 2), the uterus distends around each developing egg to form an incubatory chamber. The folds decrease in length and in correspondence to the equatorial region of the egg, the folds become larger, adhering to the shell membrane.

Bottom Line:
We found that both IL-1 and its receptor were expressed in uterine tissues before and after ovulation (in the pre-ovulatory stage, even before the yolk had formed in the ovary).However, while IL-1alpha was mostly localized in the uterine mesenchyme tissue, IL-1beta and IL-1RtI were present in the uterine epithelium.Our data provide a further comparison between the reproduction of mammals and squamate reptiles.

ABSTRACTWe recently showed that interleukin-1 (IL-1) is secreted by the placenta of a species of squamate reptile, the three-toed skink, Chalcides chalcides. In this study, we used immunohistochemical techniques to investigate the expression of IL-1 (in the two isoforms, IL-1alpha and IL-1beta) and its specific membrane receptor IL-1 RtI in uterine oviduct during the peri-implantation period. We found that both IL-1 and its receptor were expressed in uterine tissues before and after ovulation (in the pre-ovulatory stage, even before the yolk had formed in the ovary). However, while IL-1alpha was mostly localized in the uterine mesenchyme tissue, IL-1beta and IL-1RtI were present in the uterine epithelium. Our data provide a further comparison between the reproduction of mammals and squamate reptiles.